Riveting machine

ABSTRACT

A shaft moving device for elevating and lowering an operating shaft in a riveting machine. The device has a cylinder, a cylindrical member slidable up and down in the cylinder and a coaxially and rotatably supporting the operating shaft. The cylindrical member has an annular ring which also serves as a piston. A pump supplies pressure oil to the cylinder. A directional control valve is provided for selectively switching the oil supplied to the cylinder. Upper and lower ports are provided in said cylinder and are connected with the pump through the valve. The cylindrical member together with the operating shaft can be lowered and elevated by the actuation of the valve.

United States Paten Yoshikawa Mar. 19, 1974 RlVETlNG MACHINE 8/1943 Moohl ..9l/400 Primary Emminvr-Puul Mnslousky Attorney, Agent, or Firm-Wenderoth, Lind & Ponack [57] ABSTRACT A shaft moving device for elevating and lowering an operating shaft in a riveting machine. The device has a cylinder, a cylindrical member slidable up and down in the cylinder and a coaxially and rotatably supporting the operating shaft. The cylindrical member has an annular ring which also serves as a piston. A pump supplies pressure oil to the cylinder. A directional control valve is provided for selectively switching the oil supplied to the cylinder. Upper and lower ports are provided in said cylinder and are connected with the pump through the valve. The cylindrical member together with the operating shaft can be lowered and elevated by the actuation of the valve.-

1 Claim, 2 Drawing Figures 29a i i5 PATENTED MR 1 9 I974 FIG.2

FIG.1

The present invention relates to a means for elevating and lowering an operating shaft having a tool holder holding a rivet head forming tool in a riveting machine.

In the conventional riveting machines, there disadvantage that much noise was caused due to the violent blow and impact on a rivet when caulked by a rivet head forming tool actuated by a crank or a cam mechanism, whereby pains were given to workers, and also fatigue was increased in succesive caulking work which was performed by pressing a rivet with pressure given to an operating shaft by depressing a pedal adapted to elevate and lower said operating shaft with a rivet head forming tool through said crank or cam mechanism.

A first object of the present'invention is to provide a rotary pressing device in combination with a device for elevating and lowering an operating shaft with oil pressure in place of the conventional pedal actuation mechanism, and thereby noise and fatigue of workers can be decreased and efficiency of the work can be increased.

A second object of the present invention is to provide a device which can relieve an excessive load on an oil pump connected with a cylinder for actuating an operating shaft when a piston in said cylinder reaches the top dead center. i l

The features of the present invention will become apparent from the following description of a preferred embodiment of the invention described with reference to the accompanying drawings in which:

FIG. 1 is a side view of the riveting machine according to the present invention, and

FIG. 2 is an enlarged front section showing a mechanism for elevating and lowering an operating shaft together with a circuit for supplying a pressure oil.

In FIG. 1, 11 is a riveting machine, said riveting machine comprising a base member 12, a pillar l3 erected upright on said base member 12, a cylinder 14 mounted longitudinally on the upper terminal of said pillar 13, an operating shaft 15 rotatable with respect .to said cylinder 14 and moved up and down by said cylinder 14, a motor 16 connected with the upper terminal of said shaft 15, a tool holder 17 mounted on the lower terminal of said operating shaft 15, a table 18 mounted on the front middle portion of said pillar 13 and positioned just below said tool holder. 17, and a receiver 19 mounted on said table 18 for receiving a rivet head.

FIG. 2 shows an enlarged section of said cylinder 14. In the Figure, 21 is a cylindrical member penetrated downwardly through said cylinder 14 being provided a piston '22, on said cylindrical member 21 at the middle portion thereof. 23 is a top wall closing the upper ter-. minal of said cylinder, said top wall being secured tightly to said cylinder by a screw or the like and having a through hole 24 for slidably inserting the upper portion of said cylindrical member 21. Between said cylindrical tnemberZl and both terminal holes of said cylinder, one of which is the through hole 24, packings are mounted to prevent leakage.

. An upper port 25 for lowering the piston is provided on the upper portion of the cylinder and a lower port 26 for elevating the piston is provided below said port an annular ridge 27 below said port 26 is formed and on the inner periphery of the cylinder 14, and said annular ridge is adapted to tightly contact the outer surface of the cylindrical member 21.

28 is an exhaust port provided on the cylinder 14 below the annular ridge 27. 29 is an annular groove formed on the periphery of the cylindrical member 21, said groove in combination with the annular ridge 27 being adapted to communicate the port 26 with the exhaust port 28 when the piston 22 is in a top dead center position.

30 is a vertical groove formed on the periphery of the cylindrical member 21, a pin 31 screwed on the cylinder being inserted in said groove 30 for preventing rotation of the cylindrical member 21; 32 is a circuit, one end of which is connected with the exhaust port 28, the other end with a tank 33. 34 is also a circuit, one end of which is connected with the upper port 25 and 35 is a circuit one end of which is connected with the lower port 26. 36 is an oil pump driven by a motor 37. 38 is a directional control solenoid vallve of two positions, the upper two ports of which are connected with the other ends of the circuits 34, 35 respectively, the lower two ports of which are connected with the pump 36 and the tank 33 respectively.

40 is a circuit, one end of which is connected with the circuit 34 betweenthe port 25 and the valve 38, a relief valve 41 being provided on the way of said circuit 40, the other end thereof being connected to the tank 33.

The operating shaft 15 is inserted into the cylindrical member 21 through bearing 42 and is rotatably mounted therein. The motor 16 is mounted on a seat plate 43provided on the upper terminal of the cylindrical member 21, a shaft 44 of said motor 16 having .a projection 45 at the lower terminal thereof and said projection being engaged with a groove 46 provided on the upper terminal of the operating shaft 15, whereby the operating shaft can be rotated by the motor.

A tool holder 17 is screwed on the screw threaded portion 47 on the lower terminal of the operating shaft 15.

In the riveting machine as described hereinbefore, when the motor is started, oil in the tank 33 is sent to thedirectional control valve 38 by the pump 36, and if the valve 38 is positioned at the left as shown in FIG. 2, said oil is sent to the lower port 26 through the circuit 35, whereby the cylindrical member 21 is elevated by theoil pressure acting on the lower surface of the piston 22. In this condition, as the annular ridge "27 is contacted tightly with the periphery-0f the cylindrical member 21, the lower port 26 is not communicated with the exhaust port 28, therefore the elevation of the piston can be achieved without fail. -When the piston reaches to its top dead center and the annular ridge 27 corresponds with the annular groove29, the contact between the annular ridge 27 with the cylindrical member 21 is released, and the lower port 26 is communicated with the exhaust port 28 through a clearance betweenthe annular ridge 27 and the annular groove 29, the oil forced into the lower port 26 being exhausted from the port 28 to return into the tank 33, whereby the unload'circuit can be constructed for releasing the excessive load on the pump 36 at the top dead center of the piston 22.

Now the piston has been elevated and a rivet has been set on the receiver 19, and if the directional control valve 38 is switched to the right position in FIG. 2 by the actuation of solenoid, then the oil in the tank 33 is directed to the upper port 25 to lower the piston by the oil pressure acting on the upper surface thereof.

While the piston is moved toward the bottom dead center, a rivet is caulked by the rivet head forming tool mounted on the tool holder, said forming tool being rotated rockingly by the operating shaft connected with the motor 16. During this operation, the pressure on the upper port 25 is adjusted by the circuit 40.

According to the present invention, successive caulking work can be performed by an oil pressure device for elevating and lowering the operating shaft having the tool holder and switching means for supplying pressure oil to said device selectively. Therefore, such conventional disadvantages that a lot of labour was consumed and efficiency of work was decreased with the lapse of time can be removed, and decrease of fatigue of workers and increase of productivity can be achieved.

Furthermore, noises accompanied by caulking work can be decreased since the caulking work is performed by a rotary pressing device, and also a compact device is obtainable owing to the construction wherein the operating shaft 15 is disposed in the cylindrical member 21 serving also as a piston.

A further advantage of the present invention is that excessive load on the oil pump can be released by the unload circuit incorporated in the cylinder. This unload circuit is adapted not to operate during the elevation of the piston, therefore not to effect the elevation of the piston. I

What I claim is: I

1. In a riveting machine, the combination comprising an operating shaft; means for elevating and lowering said operating shaft comprised of: a cylinder having an annular ridge formed on the inner surface thereof; mounted in a coaxial relationship to, and covering said o 4 operating shaft;

a cylindrical member slidably mounted within said cylinder between said cylinder and said operating shaft and coaxially and rotatably supporting said operating shaft therein, said cylindrical member having an annular ring intermediate the ends of said cylindrical member on the periphery thereof, said cylindrical member thereby functioning as a piston, and said cylindrical member having an annular groove formed therein, said annular ridge of said cylinder adapted to normally contact the periphery of said cylindrical member and straddled said groove when said slidably mounted cylindrical member reaches a top dead center position;

a pump means for supplying pressurized oil to said cylinder;

a directional control valve operatively connected intermediate said pump means and said cylinder for selectively switching said pressurized oil supplied to said cylinder;

upper and lower ports provided on said cylinder and connected to said pump means through said valve; said annular ring being intermediate said upper and lower ports;

an exhaust port provided on said cylinder below said lower port; said exhaust port communicating with said lower port through said groove when said cylindrical member reaches its top dead center position thereby forming an unload circuit for precluding the occurance of pressure at the elevated position of said piston. 

1. In a riveting machine, the combination comprising an operating shaft; means for elevating and lowering said operating shaft comprised of: a cylinder having an annular ridge formed on the inner surface thereof; mounted in a coaxial relationship to and covering said operating shaft; a cylindrical member slidably mounted within said cylinder between said cylinder and said operating shaft and coaxially and rotatably supporting said operating shaft therein, said cylindrical member having an annular ring intermediate the ends of said cylindrical member on the periphery thereof, said cylindrical member thereby functioning as a piston, and said cylindrical member having an annular groove formed therein, said annular ridge of said cylinder adapted to normally contact the periphery of said cylindrical member and straddled said groove when said slidably mounted cylindrical member reaches a top dead center position; a pump means for supplying pressurized oil to said cylinder; a directional control valve operatively connected intermediate said pump means and said cylinder for selectively switching said pressurized oil supplied to said cylinder; upper and lower ports provided on said cylinder and connected to said pump means through said valve; said annular ring being intermediate said upper and lower ports; an exhaust port provided on said cylinder below said lower port; said exhaust port communicating with said lower port through said groove when said cylindrical member reaches its top dead center position thereby forming an unload circuit for precluding the occurance of pressure at the elevated position of said piston. 